My sister has a 3GS, we bought her an iPhone4 today as a Christmas gift. Xmas lands on a Saturday and the ATT store dude said they will be busy as hell from open to close on Sunday activating all the phones people got for Xmas. He also said it may be a problem activating the phone through ATT's phone activation line (calling in) as they will probably have a crazy amount of people calling in too. So... I have already read everything I can and watched a bunch of YouTube videos on how to cut the SIM card, I'm totally fine with doing that and more than capable of handling it. What I want to know is if I cut her SIM down to MicroSIM size and pop it in the iPhone4, do I still need to call and activate anything or will it be good to go once the card is in it? We will sync it to her iTunes, of course, but is that all? She's a really impatient person and having to wait two days after Christmas to get her phone activated will be like torture for her, and we are not going to go stand in line in the wee hours of the morning at ATT to get it activated in-store. Thanks in advance!